1. Field of the Invention
The present invention relates to a method of treating waste liquors containing phenolics and formaldehyde, particularly to a method of treating such waste liquors by a microorganism.
The term "phenolics" used herein means a compound or compounds selected from the group consisting of phenol, o-, m- and p-cresol, saligenine, o-, m- and p-hydroxybenzaldehyde, salicylic acid, catechol, 3-methylcatechol and 4-methylcatechol, etc.
2. Description of the Prior Art
Heretofore, waste liquors containing phenolics have been known which contain high concentration of formaldehyde in addition to high concentration of phenolics, such as waste liquors discharged from phenolic resin production plants and the like. Phenolics and formaldehyde have large adverse influences on biological treatment of such waste liquor due to their toxicities. A conventional process of treating such waste liquor is to dilute the waste liquor by using a large amount of dilution water or treat the waste liquor by a complicated physicochemical and/or chemical treatment to reduce their toxicities in the waste liquor, and thereafter treat the waste liquor of reduced toxicities by means of activated sludge method, as described in Japanese Patent Application laid-open No. 62,659/79. However, the method has drawbacks in that the use of a large amount of dilution water necessarily increases the amount of the waste liquor to be treated to an extremely large extent, that a cost of the dilution water is not always cheap but rather expensive, that the physicochemical and/or chemical treatment necessitates a large amount of chemicals, labours, work time and a large scale of apparatus, and that the activity of acclimated bacterium in the sludge is hardly maintained because they are weak to fluctuation in phenolics concentration of an influent waste liquor to be treated. From this reason, the inventors have formly proposed a method of treating waste liquors containing phenolics by removing phenolics by means of a microorganism of genus Aureobasidium and obtained Japanese Pat. No. 1,087,941, which was however not perfectly satisfactory.